As one of intervention treatments (intravascular treatments), there is a coiling treatment for an aneurysm. The coiling treatment is performed only when the size of a neck at the boundary between the aneurysm and the parent vessel is less than that of the aneurysm. In the case in which the size of the neck is substantially equal to that of the aneurysm, when a coil is inserted into the aneurysm, the coil is taken off from the aneurysm and embolism occurs in a peripheral vessel.
However, in recent years, a stent for a coiling treatment has been developed. In a new treatment method using the stent, as illustrated in FIGS. 19 and 20, the stent is placed into the parent vessel and the coil is inserted through a mesh of the stent. According to the new treatment method, since the mesh of the stent prevents the coil from being taken off, it is possible to select the coiling treatment, regardless of the size of the neck. FIGS. 19 and 20 are diagrams illustrating the coiling treatment using the stent.
In the coiling treatment using the stent, it is indispensable that, after the stent is placed into the parent vessel, it comes into close contact with the parent vessel and a neck portion of the aneurysm. However, in the stent for the coiling treatment, since the diameter of a metal material forming the mesh in a cross-sectional view is very small, it is very difficult to view the metal material on a radiographic image, such as a fluoroscopic image or a captured image, and it is difficult to evaluate the degree of adhesion. Therefore, in general, a doctor checks a three-dimensional image which is reconstructed in a high spatial resolution mode from projection data (hereinafter, referred to as an X-ray collection image) and checks that the stent comes into close contact with the parent vessel and the neck portion of the aneurysm. Then, the doctor performs the coiling treatment.
However, in the related art, it is difficult to clearly observe both the stent and the vessel. When the X-ray collection image is reconstructed with high resolution, the stent is clearly drawn up to a strut, but is mixed with concave and convex portions of the surface of the vessel. As a result, there is a concern that the boundary therebetween will be unclear. On the other hand, when the X-ray collection image is reconstructed with standard resolution, stent markers are drawn in the image, but the strut is not generally drawn. For example, when the number of projection directions increases in order to solve the problems, an exposure dose increases or the injection amount of contrast medium increases.